Tear Mucin Assay Kit (O-Glycan Assay Method)

Transcription

1 Product manual (O-Glycan Assay Method) Updated on Apr. 19, 2016 Ⅰ - 1 Background Mucins are major components in tear fluid and apical cell membranes on the ocular surface epithelia. Structurally, they are composed of tandem repeat domains containing heavily O-glycosylated serine and threonine residues. More than a half of its weight consists of O-glycans, which has hydrophilic nature (Fig. 1). The heavy glycosylation of mucins is believed to impart a highly negative charge and a hydrophilicity that provides a barrier to pathogen adherence and penetrance into the epithelium (Fig. 2). Alteration in both secreted and membrane-associated mucins occur in drying ocular surface diseases (Fig. 2). At the ocular surface, three types of mucins are present. The large gel-forming mucin MUC5AC is expressed by conjunctival goblet cells. Some cells of the lacrimal gland acini express the small soluble mucin MUC7. The corneal and conjunctival epithelia express the membrane-associated mucins MUCs 1, 4, and 16 (Fig. 2). alac al alac lcac alac Serine or reonine al galactose -acetylgalactosamine Core Protein ter amino acids lcac -acetylglucosamine Fig. 1 Structure of mucin Lacrimal gland MUC7 secretor, soluble Conjunctival goblet cells MUC5ACsecretor Conjunctival MUC1, MUC4, MUC16 membrane-associated mucins Lipids Aqueous Membrane mucins Gel forming mucins Microbes Normal Corneal MUC1, MUC4, MUC16 membrane-associated mucins Corneal Damaged Fig. 2 Mucins expressed around corneal surface, and barrier function by tear mucins For research use only, Not for diagnostic use. Please read this manual thoroughly before use.

2 Ⅰ - 2 Assay Principle Mucins are family of high molecular (1000 kda kda) and heavily glycosylated protein. Mucin domains within the protein core are rich in threonine and serine. The reducing ends of sugar chain N-acetylgalactosamin (GalNAc) are linked to those amino acids by the post-translational O-glicosylation (Fig.1). Mucin content can be measured as reducing ends of sugar chain after β -eliminated by diluted alkali. Reducing ends of sugar chain react at high temperatures with 2-cyanoacetamide (2-CAN) to produce intensely fluorescent condensate. Ⅰ - 3 Kit Components No. Component Volume Quantity Strage 1 Elution Buffer 30 ml 1 2 Slurry for Spin Column 45 ml 1 3 Standard Solution (GalNAc 100 µg/ml) 1.0 ml 1 4 Reagent A 0.3 ml 1 5 Reagent B 1.5 ml Stop Solution 15 ml 1 7 Empty column For 1mL 50 8 Centrifuge tube - 50 This kit contains all the components to determine the mucin contents in tear fluid. Required but not provided: Filter Paper (Schirmer strips) Micro test tube (2.0 ml, 1.5 ml, 0.5 ml) Fluorescent microplate reader and black plate (Please use a microcell when you measure with a fluorescent spectrophotometer.) II - 1 Assay Protocol Working Calibrator : N-acetylgalactosamin (GalNAc)100 µg/ml Create a standard curve by serial dilution as indicated in the table below. The remaining undiluted Standard Solution can be stored at 2-10 for 1 year. Diluted Calibrator is stable and can be stored at 2-10 for 3 weeks Conc. 100 µg/ml 50 µg/ml 25 µg/ml 12.5 µg/ml 6.25 µg/ml µg/ml µg/ml Blank Elution - Buffer Standard Solution Add 1 Add 2 Add 3 Add 4 Add 5 Add 6-2

3 II - 2 Sample Preparation Collect a tear fluid for 5 minutes using Schirmer strips. If you store the filter paper collected tear fluid, please put it in micro test tube and store it at 4. Avoid freezing. III Measurement of tear mucin 1. Transfer the Schirmer strips into micro test tube and add 200 µl of Elution Buffer, and extract mucin for 1 hour at room temperature. 2. During 1 hour extraction of step 1, prepare empty column. Set the empty column into centrifuge tube. Agitate the Slurry bottle, until uniformalized. Add 800 µl of uniformalized slurry into the empty column. Centrifuge the column for 10 minutes at 800 x g at room temperature. (Recommended equipment is a centrifugal of the swing rotor system.) Remove the pass though liquid in the bottom of centrifugal tube. 3. Charge 50 µl of the extraction from Schirmer strips prepared at step 1 onto the upper part of the packed gel of step Centrifuge the sample charged columns for 10 minutes at 800 x g at room temperature. Collect the pass through fraction (approximately 50 µl). 5. Transfer the 20 ul of each pass through fraction (4) or standard solution( 1~8 ) into the another micro test tube (for 500 ul). Add 24 ul of reagent mixture (mix together Reagent A and Reagent B, 1:5 (v/v), just before to use) to the test tube. After mixing, heat the tube up to 100 for 30 minutes. 6. Cool down the tube until room temperature, add the 200 ul of stop solution, and mix together with vortex mixer. 7. Transfer the 100 ul of the solution into the wells of 96 well black plate, and then measure the fluorescence using fluorescence plate reader set at wavelength (Exitation:336 nm, Emission:383 nm). 8. Create a standard curve by serial dilution as indicated in the below. Draw a smooth curve through these points to construct the calibration curve. Read the concentration of the sample from the calibration curve. 3

4 IV Standard Curve Ⅴ Reference data A B Changes of excitation wavelength and fluorescent wavelength in standard solution of each density A:Excitation spectrum for Emission wavelength (Em) 383 nm B:Emission spectrum for Excitation wavelength (Ex) 336 nm The recommended measurement wavelengths are 336 nm for Ex and 383 nm for Em, but you might not be able to measure the fluorescence wavelength when fluorescence plate leader with interference filter system is used. In such a case, please shift the fluorescent wavelength to longer. 4

5 VI. References 1. Gipson IK1, Hori Y, Argüeso P. Character of ocular surface mucins and their alteration in dry eye disease. Ocul Surf Apr;2(2): Argüeso P1, Balaram M, Spurr-Michaud S, Keutmann HT, Dana MR, Gipson IKGipson IK et al., Decreased levels of the goblet cell mucin MUC5AC in tears of patients with Sjögren syndrome, Invest Ophthalmol Vis Sci, Uchino Y1, Uchino M2, Yokoi N3, Dogru M1, Kawashima M1, Okada N1, Inaba T4, Tamaki S4, Komuro A3, Sonomura Y3, Kato H3, Argüeso P5, Kinoshita S3, Tsubota, Alteration of tear mucin 5AC in office workers using visual display terminals: The Osaka Study. JAMA Ophthalmol Aug;132(8): doi: / jamaophthalmol Inatomi T1, Spurr-Michaud S, Tisdale AS, Zhan Q, Feldman ST, Gipson IK. Expression of secretory mucin genes by human conjunctival epithelia. Invest Ophthalmol Vis Sci Jul;37(8): Susumu Honda, Yoshikazu Matsuda, Masaye Takahashi, and Kazuaki Kakehi, Fluorimetric Determination of Reducing Carbohydrates with2-cyanoacetamide and Application to Automated Analysis of Carbohydrates as Borate Complexes. (1980) Analytical Chemistry, Vol.52, No Crowther RS, Wetmore RF: Fluorometric assay of O-linked glycoproteins by reaction with 2-cyanoacetamide. Anal Biochem 163: , For research use only, Not for diagnostic use.